sweep tubes and audio application?

The Berning 2100 and the Counterpoint SA4 both used the now ridiculously expensive 6LF6 (though it is a very nice output tube). Expect $80-$100 per tube for NOS; you have ham operators to thank for the price.

-Richard

i thank u all...

The 6LF6 was used by Futterman in some of his OTLs. They have high-current low-voltage capability. They have become rather expensive as they are no longer made.

These days the EL509 is the tube that replaces the 6LF6 although not directly. It is a powerful sweep tube and is also used in OTLs. There is a non-plate cap variant that could be used, but FWIW the KT90 was developed from this tube, so if you really want something like that the KT90 is probably the place to look, as the design of the amp is made simpler by having no plate caps and the use of octal sockets.

Thanks!

I appreciate the clear and concise explanations. Just the info I was looking for, no more no less.

I've come to despise ham radio explanations on certain information. They are almost always too wordy, and poorly written. Often, in their attempts to appear intelligent and articulate, they achieve neither.

Thanks again

My Acoustat servo amps for my AcoustatX speakers use 4 6HB5 tubes per amp, and it's also an OTL.
Made in the mid 1970's ,they have stood the test of time.

So using TV tubes isn't something new.